The Effect of Accommodation on Retinal Image Size

Abstract

The apparent size of an object is diminished when accommodation of the eye moves inward to a position closer to the observer than to a viewed object. This phenomenon is called accommodation micropsia. Using schematic eyes, we investigated change in retinal image size caused by a change in accommodation. The use of schematic eyes is also discussed and is justified. The calculated magnitude of this diminution for four schematic eyes ranged from unity at infinity to a maximum of 0.98 (- 2%) at about 12.0 diopters (D). For distances at which accommodation micropsia is typically observed (about 2.0 D), retinal minification is less than 0.997 (- 0.3%). Thus changes in the size of the retinal image attributable to accommodation are virtually negligible when compared with the observed reduction of 3% to 33%. This suggests that accommodation micropsia is mediated almost entirely by processes other than those involving the optics of the eye.

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References

Biersdorf, W. R. , and Baird, I. C. (1966). Effects of an artificial pupil and accommodation on retinal image size. Journal of the Optical Society of America, 56, 1123–1129.

Blaker, I. W. (1980). Toward an adaptive model of the human eye. Journal of the Optical Society of America, 70, 220–223.

Davson, H. (1980). Physiology of the eye (4th ed.). Edinburgh, Scotland: Churchill Livingstone.

Emsley, H. H. (1953). Visual optics (5th ed., Vol. I). London: Butterworths.

Heinemann, E. G. , Tulving, E. , and Nachmias, J. (1959). The effect of oculomotor judgments on apparent size. American Journal of Psychology, 74, 440–445.

Hochberg, J. (1972). Perception II: Space and movement. In J. W. Kling and L. A. Riggs (Eds.), Woodworth and Schlosberg's experimental psychology (pp. 475–550). London: Methuen.

Hollins, M. (1976). Does accommodation micropsia exist?. American Journal of Physiology, 89, 443–454.

lavecchia, J. H. , lavecchia, H. P. , and Roscoe, S. N. (1983). The moon illusion revisited. Aviation, Space and Environmental Medicine, 54, 39–46.

LeGrand, Y. , and El Hage, S. (1980). Physiological optics. Berlin: Springer-Verlag.

10.

Leibowitz, H. W. , and Owens, D. A. (1975a). Anomalous myopias and the intermediate dark focus of accommodation. Science, 189, 646–648.

11.

Leibowitz, H. W. , and Owens, D. A. (1975b). Night myopia and the intermediate dark focus of accommodation. Journal of the Optical Society of America, 65, 1121–1125.

12.

Leibowitz, H. W. , and Owens, D. A. (1978). New evidence for the intermediate position of relaxed accommodation. Documenta Ophthalmologica, 46(1), 133–147.

13.

Longhurst, R. S. (1973). Geometrical and physical optics (3rd ed.). London: Longman.

14.

Marsh, J. S. , and Temme, L. A. (1990). Optical factors in judgments of size through an aperture. Human Factors, 32, 109–118.

15.

Meehan, J. W. (1990). Apparent minification in an imaging display. Unpublished doctoral dissertation, Monash University, Melbourne, Australia.

16.

Meehan, J. W. , and Triggs, T. J. (1988). Magnification effects with imaging displays depend on scene content and viewing condition. Human Factors, 30, 487–494.

17.

Navarro, R. , Santamaria, J. , and Bescos, J. (1985). Accommodation-dependent model of the human eye with aspherics. Journal of the Optical Society of America, A2, 1273–1281.

18.

Pascal, J. I. (1952). Effect of accommodation on the retinal image. British Journal of Ophthalmology, 36, 676–678.

19.

Randle, R. J. , Roscoe, S. N. , and Petitt, J. C. (1980). Effects of magnification and visual accommodation on aim-point estimation in simulated landings with real and virtual image displays (NASA Tech. Paper 1635). Washington, DC: National Aeronautics and Space Administration.

20.

Rock, I. (1975). An introduction to perception. New York: Macmillan.

21.

Roscoe, S. N. (1979). When day is done and shadows fall, we miss the airport most of all. Human Factors, 21, 721–731.

22.

Roscoe, S. N. (1984). Judgments of size and distance with imaging displays. Human Factors, 26, 617–629.

23.

Roscoe, S. N. (1989). The zoom-lens hypothesis. In M. Hershenson (Ed.), The moon illusion (pp. 31–57). Hillsdale, NJ: Erlbaum.

24.

Von Kries, J. (1962). Notes on Chapter 30. In J. P. C. Southall (Ed. and Trans.), Helmholtz's treatise on physiological optics (pp. 369–400). New York: Dover. (Original work published 1924)

25.

Wheatstone, C. (1983). Contributions to the physiology of vision: Part the second. On some remarkable, and hitherto unobserved, phenomena of binocular vision. In N. J. Wade (Ed.), Brewster and wheatstone on vision (p. 153). London: Academic. Reprinted from Philosophical Transactions of the Royal Society, 1852, 142, 1-17)